1. Field of the Invention
The present invention relates to an air conditioner and more particularly to an air conditioner coolant circulation route changing apparatus by which efficiency is substantially improved for cooling and heating operations.
2. Description of the Prior Art
A conventional air conditioner is classified into a variety of types according to its functions and composition of its units. The air conditioner is classified into an exclusive cooling use, an exclusive cooling and dehumidifying use, a dual function of cooling cum heating operations according to its functions, while being classified into an integral type having integrated functions of cooling and heating operations and being installed on a window and a separate type having a cooling apparatus disposed at a room, a heating apparatus and a compressor placed at the outside of the room according to the composition of its units.
In the aforementioned air conditioner of a dually functioned heating cum cooling operations, an indoor unit (10) installed in the room and an outdoor unit (20) may be operated as an integral system, as necessary, for the heating or cooling operation.
The separate type of air conditioner is made up of the indoor unit (10) and the outdoor unit (20) as illustrated in FIGS. 1 and 2. The outdoor unit (20) includes a compressor (30) for compressing a coolant into that of high temperature and high pressure, an outdoor heat-exchanger (40) for heat-exchanging the compressed coolant of high temperature and high pressure with outdoor air by way of cooling and condensation, a cooling capillary tube (50) and a heating capillary tube (51) for passing and expanding the coolant of room temperature and high pressure cooled and condensed at the outdoor heat-exchanger (40) into the coolant of low temperature and low pressure. On the other hand, the indoor unit (10) includes an indoor heat-exchanger (60) for changing the coolant passed through the cooling capillary tube (50) into gaseous coolant of low temperature and low pressure in vaporization, thereby heat-exchanging with the room air at the indoor heat-exchanger (60).
At one side of the compressor (30) is a four way valve (70) of an applied electronic valve for changing the circulation routes of the coolant, where the compressed coolant of high temperature and high pressure from the compressor (30) flows into the outdoor heat-exchanger (40) for the cooling operation, and into the indoor heat-exchanger (60) for the heating operation.
In the air conditioner, the cooling cycle is depicted by solid arrows in FIG. 1 for the cooling operation, where the gaseous coolant of high temperature and high pressure discharged from the compressor (30) of the outdoor unit (20) is passed through the four way valve (70), cooled and condensed at the outdoor heat-exchanger (40), thereby being heat-exchanged with the outdoor air. The liquid coolant of room temperature and high pressure passed through the outdoor heat-exchanger (40) is infused into the cooling capillary tube (50), changed into a coolant of low temperature and low pressure in expansion heat-exchanged cooled and infused into the indoor heat-exchanger (60) inside of the indoor unit (10).
The liquid coolant is vaporized at the indoor heat-exchanger (60), thereby changing into a perfect gas coolant of low temperature and low pressure. Then, the gaseous coolant at the indoor heat-exchanger (60) is heat-exchanged with the room air, thereby cooling the room at low temperature.
Accordingly, the gaseous coolant of low temperature and low pressure is infused into the compressor (30) and changed into a gaseous coolant of high temperature and high pressure by way of the heat insulation and compression reactions. Therefore, the cooling cycle is to be repeated as described above.
On the other hand, the heating cycle is carried out in the dotted arrow direction in FIG. 1 for the heating operation, where the coolant is circulated to heat the room at an opposite direction to that for the cooling operation.
However, in the air conditioner described above, as illustrated in FIG. 2, the indoor heat-exchanger (60), used as a vaporizer during the cooling operation and as a condenser during the heating operation, is designed to let the coolant flow at the straight arrow direction during the cooling operation, from its outlet (62) to its inlet (61). The air flowing into the indoor unit (10) flows from a room air suction side (O) toward inside of the indoor unit (I). At that time, the temperature of the coolant inside of the indoor unit (I), close to the inlet (61), at A part shown in the drawings, is lower than the temperature of the coolant at the room air suction side (O), close to the outlet (62) of the indoor heat-exchanger (60).
The coolant is circulated in a reverse direction, i.e., in the dotted arrow direction during the heating operation, enabling the coolant to flow from the inlet (61) of the indoor heat-exchanger (60) to its outlet (62), where the cold air in the room flows from the room air suction inlet (O) to the indoor unit (I). At that time, the temperature of the coolant at the A part in the drawings is lower than the temperature of the coolant at the room air suction side (O). Due to the aforementioned reasons, there are problems in the conventional air conditioner in that the efficiency of the heating operation is substantially deteriorating and same is applied to the cooling operation when the heating operation is changed into the cooling operation.